To date designs and methods of manufacturing photonics transmit/receive modules have relied on complicated techniques of aligning the light emitting and detecting elements, of encapsulating said elements, and of combining the carrier with an optical connector. This is especially true of arrays combining one or more light emitting or detecting devices in parallel. Attempts at handling Vertical Cavity Surface Emitting Lasers or VCSELs and their arrays, as well as photodetectors and their arrays for use in fiber Tx, Rx and Tx/Rx packages have often involved changing the optical axis of the chips—allowing them to interface with v-grooves in a silicon substrate such as in U.S. Pat. No. 5,337,391. Other groups have employed methods to change the optical axis that employ the use of angle polished fiber or flexible waveguide arrays such as Hewlett Packard's Parallel Optical Link Organization (POLO) [Hahn, K. H. PLOL “Parallel optical links for gigabyte data communications”, in the Proceedings of the 45th Electronics Components and Technology Conference Proceedings, pgs. 7-8]. Other designs have involved several complicated parts such as U.S. Pat. No. 5,337,398, or have involved the mounting of devices on an optical jumper block such as U.S. Pat. No. 5,719,978 or on the endface of a polished fiber array block such as in the Motorola Optobus [Schwartz, D. B., C. K. Y. Chun, B. M. Foley, D. H. Hartman, M. Lebby, H. C. Lee, C. L. Sheih, S. M. Kuo, S. G. Shook, and B. Webb, 1995, a low cost, high performance optical interconnect. In the Proceedings of the 45th Electronics Components and Technology Conference, pgs. 376-379. Piscataway, N.J.: IEEE]. All of these references are hereby incorporated by reference herein. One prior attempt at monolithic integration using stacks of self aligned chips utilized ball lenses between the stacks to couple optical fibers to the optically active device as was seen in U.S. Pat. No. 5,259,054.
These earlier methods of handling optically active elements, especially surface emitting or receiving devices as arrays—as well as positioning of discrete components—has been very complex, expensive, and lacking in simplicity of design thus making the designs non usuable in the current manufacturing climate. The current invention relates to a new technique for creating a “face-plate” module for handling such active devices. The invention has wide application in making connection to existing and future parallel optical fiber array connectors in its ability to use modified existing ferrules and their alignment mechanisms and accurately align the optical elements of the carrier to the optical fibers.
This eliminates all need for expensive and hard to machine components, costly labor machining and complicated assembly techniques. The device is exceptionally useful for creating cost effective small form factor transceivers and parallel Tx/Rx modules. The invention allows a greater degree of monolithic integration than previously possible and eliminates many of the parts and steps previously required such as optical jumper blocks, polishing operations, etc. Such steps are very expensive to perform and time consuming thus adding to the price of the component member. The invention also will find application in chip to chip and board to board interconnects allowing easier cost effective packaging of the optical elements.
New and existing technologies in micromachining of silicon and other materials allow a greater degree of precision to be obtained in forming cavities and holes in substrates. For example the Bosch process has demonstrated through-wafer etching with excellent control of dimensions at etch rates making new mechanical structures possible. Newer deep dry etching technologies and wet anisotropic technologies—that have already been demonstrated in silicon wafers in conjunction with better encapsulants—make manufacture of these devices possible at this time. It is expected similar etching technologies will become available for other ceramic, glass, injection or transfer molded plastics, and other materials. In addition, parts of the design may find economic manufacture in the future using molding processes, laser machining, light/laser assisted chemical machining, etc.
The devices disclosed are various embodiments of a novel carrier for utilizing one or more optically active devices or elements (here meaning lasers such as VCSELs and VCSEL arrays, photodetectors and photodetector arrays, Light Emitting Diodes or LEDs, Super Luminescent LEDs or SLEDs, etc.) allowing them to be precisely positioned, electrically connected, encapsulated, optionally lensed, and heat sinked. The applications include chip to chip, board to board, and fiber optic and especially fiber optic array transmit, receive and transceiver modules. The approach disclosed can eliminate the need for polishing an assembly to form an optical surface, active alignment of the active optical elements to the carrier, and/or active alignment of the carrier to a connector assembly. Patterned metallizations and solders become incorporated in this design using techniques such as shadow masking, lift-off, selective CVD metal deposition, and can be combined with plating using electroless methods or any of the known electroplating techniques.